Abstract: In order to understand the effect of alloying elements of Cr and Al on electrochemical corrosion behavior of J55 steel, the steel's electrochemical corrosion behavior in 3.5wt% NaCl solution was investigated by electrochemical measuring and immersion testing. The results show that, after adding 1.49wt% Cr, 1.47wt% Al and 1.98wt% Cr, 1.95wt% Al into J55 steel, open corrosion potention (E_ocp) or self-corrosion potential of the alloyed J55 steel moved to the positive direction, this indicating the reduction of corrosion activity. The alloyed steels exhibited higher corrosion resistance, lower corrosion current density and lower corrosion rate. After the alloyed steels were immersed in NaCl solution for 200 d, protective corrosion product with Cr- and Al-rich was found on the surface of the steels, the corrosion resistance of the steel was increased by the corrosion product.